JP2013032814A - Unload device of working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively obtain an unload device of a working machine, which discharges a pressure oil from a hydraulic pump to an unload oil passage by a changeover valve at the stop of hydraulic actuators.SOLUTION: The unload device of the working machine comprises an on-off valve 105 which can switch a state to an opened state that the pressure oil is discharged to the discharge oil passage 104 from a back oil chamber of the changeover valve 102 and a closed state that the discharge of the pressure oil is stopped, and a control valve 107 which switches the on-off valve 105 by pilot hydraulic pressure. When actuator drive circuits 30, 40 are operated for driving the hydraulic actuators 18, 21, the control valve 107 switches the on-off valve 105 to the closed state, and when the actuator drive circuits 30, 40 are operated for stopping the hydraulic actuators 18, 21, the control valve 107 switches the on-off valve 105 to the opened state.

Description

  The present invention relates to an unloading device for a work machine.

  Conventionally, for example, there has been a hydraulic drive device disclosed in Patent Document 1. This hydraulic drive device includes an unload circuit that connects a hydraulic oil supply path that connects a hydraulic pump and a direction switching valve of a hydraulic actuator to a tank port, and the unload circuit includes a logic valve and a sub spool. ing. When the main spool that constitutes the direction switching valve is closed by operation through the pilot pressure by the pilot valve, the sub spool is opened by operation through the pilot pressure by the pilot valve, and the back pressure chamber of the logic valve Is connected to the tank port by the sub spool, the logic valve is opened, and the pressure oil discharged from the hydraulic pump flows to the tank through the tank port via the logic valve.

JP-A-10-238506

For those equipped with a hydraulic actuator, a switching valve that acts on the pressure oil supply path that supplies pressure oil from the hydraulic pump to the actuator drive circuit is provided, and when operated to stop the hydraulic actuator, the switching valve switches to the open state. If it is configured to allow pressure oil to flow from the pressure oil supply path to the unload oil path, the hydraulic oil supplied from the hydraulic pump to the pressure oil supply path will flow to the unload oil path when the hydraulic actuator is stopped. The driving load of the hydraulic pump when the hydraulic actuator is stopped can be reduced.
Opening that discharges pressure oil from the back pressure chamber to the oil discharge passage when it is configured to be closed by the back pressure in the back pressure chamber. An on-off valve that can be switched between a state and a closed state in which the discharge of pressure oil is stopped is provided, and the switching valve is switched between an open state and a closed state by the on-off valve.
When the conventional technique is employed to link the opening / closing valve to the actuator drive circuit so that the switching operation of the opening / closing valve is performed by the linking means, there is a problem that is disadvantageous in terms of economy.
In other words, when the conventional technology is adopted, the switching valve is opened / closed only by the opening / closing valve. Therefore, an opening / closing valve with a large switching resistance due to pressure oil acting on the back pressure chamber of the switching valve is provided. For example, in order to employ a linkage means using electric or electronic control, the on-off valve generates a strong switching force by inputting an operation signal from the linkage means. Therefore, an expensive on-off valve having a function of generating a strong switching force has been required.

  An object of the present invention is to provide an unloading device for a working machine that can be obtained at low cost while allowing hydraulic oil from a hydraulic pump to flow into an unloading oil passage by a switching valve when the hydraulic actuator is stopped. is there.

The unloading device for a work machine according to the first invention is:
Switchable between an open state allowing pressure oil flow from the pressure oil supply path for supplying pressure oil from the hydraulic pump to the actuator drive circuit to the unload oil path and a closed state stopping the pressure oil flow; and A switching valve operated to the closed state by pressure oil from the pressure oil supply passage acting on a back pressure chamber;
An open / close valve that is switchable between an open state for discharging pressure oil from the back pressure chamber to the oil discharge passage and a closed state for stopping discharge of the pressure oil;
A control valve for switching the on-off valve by pilot hydraulic pressure,
When the actuator drive circuit is operated to drive a hydraulic actuator, the control valve switches the on-off valve to the closed state, and when the actuator drive circuit is operated to stop the hydraulic actuator, the control The actuator drive circuit and the control valve are linked so that the valve switches the open / close valve to the open state.

  According to the configuration of the first aspect of the invention, when the actuator drive circuit is operated to stop the hydraulic actuator, the control valve is switched in cooperation with the actuator drive circuit, and the open / close valve is switched to the open state by the pilot hydraulic pressure. The valve discharges the pressure oil from the back pressure chamber of the switching valve and switches the switching valve to the open state, and the pressure oil discharge from the pressure oil supply path to the unload oil path is permitted by the switching valve and supplied from the hydraulic pump. The compressed pressure oil can be discharged to the unload oil passage.

  Since the switching of the on / off valve is performed by operating the pilot hydraulic pressure by the control valve, the on / off valve is switched against the switching resistance generated due to the pressure oil acting on the back pressure chamber of the switching valve. The operation force applied by the pilot oil pressure can be made smoothly, eliminating the need to provide a strong switching force for the on-off valve, and allowing the control valve to be operated lightly against the pilot oil pressure. I can finish it.

  Therefore, when the hydraulic actuator is stopped, the pressure oil from the hydraulic pump is allowed to flow out to the unload oil passage by the switching valve to reduce the driving load of the hydraulic pump. It can be obtained at low cost by having a simple function that does not have a force generation function or can be operated lightly.

  In the second aspect of the invention, the valve body of the switching valve and the spool of the control valve are aligned in the sliding direction of the valve body, and the spool of the control valve and the spool of the on-off valve are slid on the valve body. The valve body, the spool of the control valve, and the spool of the on-off valve are incorporated in a valve case in an array arranged in a direction orthogonal to the direction.

  According to the configuration of the second aspect of the invention, the switching valve, the on-off valve and the control valve are collected in a compact state in which the switching valve, the on-off valve and the control valve are dispersed so as not to overlap in the direction perpendicular to the sliding direction of the valve body. Can be equipped.

  Accordingly, the switching valve, the on-off valve and the control valve are provided to enable the hydraulic oil to flow out to the unload oil passage when the hydraulic actuator is stopped. It is possible to equip the fuselage in a compact manner.

  According to the third aspect of the present invention, the valve case is configured by integrally forming a valve case portion of the switching valve, a valve case portion of the on-off valve, and a valve case portion of the control valve.

  According to the structure of this 3rd invention, the valve case part of a switching valve, the valve case part of an on-off valve, and the valve case part of a control valve can be formed integrally, and can be obtained compactly.

  Accordingly, a switching valve, an on-off valve, and a control valve are provided to enable the hydraulic oil to flow out from the hydraulic pump to the unload oil passage when the hydraulic actuator is stopped. Can be installed in a compact body from the surface of the valve case.

  In the fourth aspect of the invention, as the hydraulic actuator, an elevating cylinder for elevating the working device with respect to the traveling machine body is provided.

  According to the fourth aspect of the present invention, when the actuator drive circuit is operated to drive the lift cylinder, the control valve is switched in cooperation with the actuator drive circuit, and the on-off valve is switched to the closed state by the pilot hydraulic pressure. The on / off valve stops the pressure oil discharge from the back pressure chamber of the switching valve and switches the switching valve to the closed state, and the hydraulic oil discharge from the pressure oil supply path to the unload oil path is stopped by the switching valve to Pressure oil supplied from the pump can be supplied to the lifting cylinder to drive the lifting cylinder.

  When the actuator drive circuit is operated to stop the elevating cylinder, the switching valve is switched to the open state via the on / off valve by the control valve that is switched by linkage with the actuator drive circuit, and is supplied from the hydraulic pump Pressure oil can be discharged to the unload oil passage.

  Therefore, when the lifting / lowering operation of the work device is stopped, the pressure oil from the hydraulic pump flows out into the unload oil passage, and the driving load of the hydraulic pump can be reduced.

  The fifth aspect of the present invention includes a rolling cylinder that performs a rolling operation of the work device with respect to the traveling machine body as the hydraulic actuator.

  According to the fifth aspect of the present invention, when the actuator drive circuit is operated to drive the rolling cylinder, the control valve is switched in cooperation with the actuator drive circuit, and the on-off valve is switched to the closed state by the pilot hydraulic pressure. The on / off valve stops the pressure oil discharge from the back pressure chamber of the switching valve and switches the switching valve to the closed state, and the hydraulic oil discharge from the pressure oil supply path to the unload oil path is stopped by the switching valve to Pressure oil supplied from the pump can be supplied to the rolling cylinder to drive the rolling cylinder.

  When the actuator driving circuit is operated to stop the rolling cylinder, the switching valve is switched to the open state via the on / off valve by the control valve that is switched by linking with the actuator driving circuit, and is supplied from the hydraulic pump. Pressure oil can be discharged to the unload oil passage.

  Therefore, when the rolling operation of the working device is stopped, the pressure oil from the hydraulic pump flows out into the unload oil passage, and the driving load of the hydraulic pump can be reduced.

It is a side view which shows the whole tractor. It is a perspective view which shows a link mechanism and a rotary tillage apparatus. It is a hydraulic circuit diagram which shows the hydraulic circuit which enables the drive of a low rig cylinder and a raising / lowering cylinder. FIG. 3 is a hydraulic circuit diagram showing a brake hydraulic circuit, a steering hydraulic circuit, a transmission hydraulic circuit, and a work hydraulic circuit. It is the schematic which shows an unloading apparatus. It is a top view which shows a valve apparatus. It is a side view which shows a valve apparatus. FIG. 7 is a cross-sectional view taken along line VIII-VIII in FIG. 6. It is sectional drawing which shows a valve apparatus provided with another embodiment.

  Hereinafter, a case where a tractor is equipped with an unloading device for a work machine according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the tractor is equipped with a pair of left and right front wheels 1, 1 that can be steered and driven and a pair of left and right rear wheels 2, 2 that can be driven. A driving unit 4 having a driver's seat 4 a is provided to form a traveling body, and a rotary tiller 7 is connected to a rear end of a mission case 5 that constitutes a rear part of the body frame 3 via a link mechanism 6. It is configured.

  The vehicle body frame 3 of the traveling machine includes an engine 8, a transmission case 10 having a front end connected to a rear portion of the engine 8 via a clutch housing 9, and a transmission case having a front end connected to a rear end of the transmission case 10. 5 and a front wheel support frame 11 connected to the lower part of the engine 8.

  The traveling machine body includes a power take-out shaft 12 projecting rearward from the rear wall of the transmission case 5, and transmits the driving force from the engine 8 from the power take-out shaft 12 to the rotary tiller 7 through the rotary shaft 13. To do.

  FIG. 2 is a perspective view showing the link mechanism 6 and the rotary tiller 7. As shown in FIG. 1 and FIG. 1, the link mechanism 6 includes a pair of left and right lift arms 15, 15 that are supported by a support portion 5 a provided on the upper portion of the mission case 5 so as to be swingable up and down, and a lower portion of the mission case 5. A pair of left and right lower links 16, 16 extending from the pair of left and right lower support bodies 5 b, 5 b provided in the upper and lower sides to freely swing up and down, and the left lift arm 15 and the left lower link 16 are connected. The lift rod 17, the double-acting rolling cylinder 18 that connects the right lift arm 15 and the right lower link 16, and the upper support 5 c provided on the rear wall of the transmission case 5 can swing up and down backward. And a top link 19 extending in the direction. The extended ends of the pair of left and right lower links 16 and 16 and the top link 19 are connected to a connecting frame 20 provided in the rotary tiller 7.

  The link mechanism 6 includes a pair of left and right single-acting lifting cylinders 21 and 21 that are connected at one end to a pair of left and right lift arms 15 and 15 and connected at the other end to a pair of left and right lower supports 5b and 5b. The pair of left and right lift arms 15, 15 are swung up and down by the pair of left and right lifting cylinders 21, 21, and are swung up and down with respect to the mission case 5, so that the rotary tiller 7 is moved with respect to the traveling machine body. To move up and down.

  The link mechanism 6 is configured such that the lower link 16 on the right side is moved up and down with respect to the transmission case 5 by the rolling cylinder 18, thereby connecting the lower link 16 with the lower support 5 b and the connection frame 20, the lift rod 17 and the lift. Due to the flexibility provided at the connection point between the arm 15 and the lower link 16, the connection point between the rolling cylinder 18 and the lower link 16 and the lift arm 15, and the connection point between the top link 19, the upper support 5 c and the connection frame 20. Then, the rotary tiller 7 is subjected to a rolling operation with respect to the traveling machine body.

  A hydraulic circuit that enables driving of the rolling cylinder 18 and the lifting cylinder 21 is configured as shown in FIG. In other words, an actuator drive circuit 30 for the rolling cylinder is configured by including an operation valve 32 connected to the rolling cylinder 18 via a pair of operation oil passages 31, 31. A hydraulic oil supply passage 26 is connected to the discharge part of the hydraulic pump 25, and an ascending / descending operation valve 42 and a descending operation valve 43 connected to a pair of elevating cylinders 21 and 21 via an operating oil passage 41 are provided. A cylinder actuator drive circuit 40 is configured, and an input port 44 of the actuator drive circuit 40 is connected to an oil discharge port 34 of the actuator drive circuit 30 for the rolling cylinder via the relay oil passage 27, so as to be used for the lift cylinder. The input port 44 of the actuator drive circuit 40 is configured to be connected to the pressure oil supply path 26.

  The pressure oil supply path 26 includes a pump-side supply path 26 a that connects the discharge portion of the first hydraulic pump 25 to the input port 51 of the oil extraction circuit 50, a main extraction oil path 52 provided in the oil extraction circuit 50, An actuator-side supply path 26b that communicates the oil discharge port 53 of the oil take-out circuit 50 with the input port 33 of the actuator drive circuit 30 for the rolling cylinder is configured. A relief oil passage 28 having a relief valve 28a is connected to the pump side supply passage 26a. A main take-out oil passage 52 of the oil take-out circuit 50 is provided in a state where the input port 51 and the oil discharge port 53 are communicated with each other.

  The oil take-out circuit 50 includes a pair of take-out port portions 55, 55 connected to the main take-out oil passage 52 via a pair of branch take-out circuits 54, 54, and an input hose of an external device such as an earth breaker serves as a take-out port portion. 55, the takeout valve 56 provided in the branch takeout circuit 54 is operated, and the branch takeout circuit 54 is opened by the opening action of the takeout valve 56 and the switching valve 57, whereby the first hydraulic pump 25 is operated. The pressure oil supplied to the main take-out oil passage 52 is supplied to the external device through the pump side supply passage 26a. An oil discharge passage 58 having an opening / closing valve 58a is connected to one outlet 55, and the oil returning from the external device is discharged from the oil discharge passage 58 to the drain oil passage 59 by opening the opening / closing valve 58a. So that it can be returned to the mission case 5 as a tank.

  The actuator driving circuit 30 for the rolling cylinder includes the operation valve 32, an oil supply path 35 connecting the operation valve 32 to the input port 33, and a switching valve 36 provided in the oil supply path 35 as an oil discharge port 34. An oil discharge passage 37 to be communicated, a pair of control valves 38 and 38 respectively connected to a pair of operation portions of the operation valve 32 via a pair of pilot operation oil passages 38a and 38a, and a pair of control valves 38 and 38 And a pilot oil passage 38b connected to the.

  The pair of operating oil passages 31, 31 connecting the operating valve 32 and the rolling cylinder 18 includes a pilot check valve 39. A pilot oil passage 39 a having a shuttle valve is provided between the pilot check valve 39 and the switching valve 36. The pilot oil passage 38b is connected to the pump side supply passage 26a. The pilot oil passage 38b includes an unloaded pressure control valve 38c and a pressure detection port 38d for detecting the pilot pressure.

  Accordingly, in the actuator driving circuit 30 for the rolling cylinder, when one control valve 38 is controlled to be switched to the driving position and the other control valve 38 is controlled to be switched to the neutral position, the pump side supply path 26a and the pilot oil path 38b are controlled. Is supplied from one control valve 38 to one operation portion of the operation valve 32 via the pilot operation oil passage 38a, and the operation valve 32 is switched to the actuator drive position to thereby operate the first hydraulic pump. The pressure oil supplied from the pressure oil supply path 26 to the pressure oil supply path 26 and supplied from the pressure oil supply path 26 to the oil supply path 35 is supplied from the operation valve 32 to the bottom port of the rolling cylinder 18 through one operation oil path 31. Then, the rolling cylinder 18 is driven to the extension side.

  The actuator drive circuit 30 for the rolling cylinder is supplied from the pump side supply passage 26a to the pilot oil passage 38b when one control valve 38 is controlled to be switched to the neutral position and the other control valve 38 is controlled to be switched to the drive position. The pilot hydraulic pressure is supplied from the other control valve 38 to the other operation portion of the operation valve 32 via the pilot operation oil passage 38a, and the operation valve 32 is switched to the actuator drive position. The pressure oil supplied to the pressure oil supply passage 26 and supplied from the pressure oil supply passage 26 to the oil supply passage 35 is supplied from the operation valve 32 to the rod side port of the rolling cylinder 18 via the other operation oil passage 31. The cylinder 18 is driven to the shortening side.

  The actuator drive circuit 30 for the rolling cylinder discharges the pilot hydraulic pressure from the pair of operation portions of the operation valve 32 by the pair of control valves 38, 38 when the pair of control valves 38, 38 are both controlled to be switched to the neutral position. Thus, the operation valve 32 is switched to the neutral position, the supply of pressure oil to the bottom side port and the rod side port of the rolling cylinder 18 is stopped, and the rolling cylinder 18 is stopped.

  The actuator driving circuit 40 for the lifting cylinder includes the lifting operation valve 42 and the lowering operation valve 43, and a lifting control valve 45 connected to the operating portion of the lifting operation valve 42 via a pilot operation oil passage 45 a, A lowering control valve 46 connected to the operating portion of the lowering operation valve 43 via a pilot operation oil passage 46a, an oil supply passage 47 for communicating the ascending operation valve 42 to the input port 44, an ascent control valve 45 and a lowering control valve 46 And a pilot oil passage 48 connected to the pipe.

  The pilot oil passage 48 is communicated with a portion of the operation oil passage 41 where the ascending operation valve 42 and the descending operation valve 43 are connected. A relief oil passage 49 having a relief valve 49 a is connected to the oil supply passage 47.

  Therefore, when the lift control valve 45 is controlled to be switched to the drive position, the actuator drive circuit 40 for the lift cylinders causes the pilot hydraulic pressure supplied from the operation oil passage 41 to the pilot oil passage 48 to be supplied from the lift control valve 45 to the pilot operation oil. The operation valve 42 is supplied to the operating portion of the ascending operation valve 42 via the path 45a to switch the ascending operation valve 42 to the actuator drive position, and is supplied from the first hydraulic pump 25 to the pressure oil supply path 26. The hydraulic pressure supplied to the oil supply passage 47 via the relay oil passage 27 is supplied to the bottom chambers of the pair of lift cylinders 21, 21 from the lift operation valve 42 via the operation oil passage 41, and the pair of lift cylinders 21, 21. Is driven to the extension side (the tillage device ascending side). At this time, the pressure oil supplied from the ascending operation valve 42 to the elevating cylinder 21 passes through the check valve 41b among the throttle portion 41a and the check valve 41b provided in parallel with the operation oil passage 41.

  When the lowering control valve 46 is controlled to be switched to the lowering operation position, the actuator driving circuit 40 for the lifting cylinders causes the pilot hydraulic pressure supplied from the operating oil passage 41 to the pilot oil passage 48 to be supplied from the lowering control valve 46 to the pilot operation oil passage. 46a is supplied to the operating portion of the lowering operation valve 43 to switch the lowering operation valve 43 to the oil discharge position, and pressure oil is supplied from the pair of lifting cylinders 21 and 21 to the lowering operation valve 43 via the operation oil passage 41. And the pair of elevating cylinders 21 and 21 are operated to the shortening side (the tilling device descending side) by the load of the rotary tilling device 7. At this time, the pressure oil discharged from the pair of elevating cylinders 21 and 21 passes through the throttle portion 41 a for adjusting the drop speed in the operation oil passage 41.

  In the actuator driving circuit 40 for the lifting cylinder, when the raising control valve 45 and the lowering control valve 46 are controlled to be switched to the stop position, the lifting operation valve 42 is switched to the oil supply stop position, and the lowering operation valve 43 is set to the lock position. When the switching operation is performed, the ascending operation valve 42 and the descending operation valve 43 stop the pair of elevating cylinders 21 and 21.

  An oil passage block 5d shown in FIG. 3 is an upper cover provided in the mission case 5.

  The brake hydraulic circuit 60 shown in FIG. 4 constitutes a brake operating device such that when the brake pedal 61 is stepped on, the master cylinder 62 is operated and the brake 63 is braked.

  The steering hydraulic circuit 65 shown in FIG. 4 constitutes a power steering device such that when the steering handle 66 is rotated, the steering valve 67 and the metering pump 68 are operated to drive the power steering cylinder 69. It is.

  The shift hydraulic circuit 70 shown in FIG. 4 constitutes a transmission that shifts the traveling transmission, and includes a first speed piston 71, a second speed piston 72, a third speed piston 73, a fourth speed piston 74, a forward piston 75, and a reverse speed. A piston 76, a low speed piston 77, a high speed piston 78, a front wheel differential piston 79, a rear wheel differential piston 80, a drive switching piston 81, and a front wheel acceleration piston 82 are provided. The first to fourth speed pistons 71, 72, 73, and 74 change the traveling transmission from the first speed to the fourth speed state by switching the first speed to the fourth speed clutch of the main transmission unit. The forward piston 75 and the reverse piston 76 are operated to switch between the forward clutch and the reverse clutch of the forward / reverse switching portion to shift the traveling transmission between the forward transmission state and the reverse transmission state. The low speed piston 77 and the high speed piston 78 are operated to switch the sub-transmission unit between the low speed state and the high speed state to sub-shift the traveling transmission between the low speed side and the high speed side. The front wheel differential piston 79 switches the front wheel differential mechanism to the differential lock state, and the rear wheel differential piston 80 switches the rear wheel differential mechanism to the differential lock state. The drive switching piston 81 switches the traveling transmission between a four-wheel drive state and a two-wheel drive state. The front wheel acceleration piston 82 switches the front wheel acceleration by the traveling transmission between an on state and an off state.

  The work hydraulic circuit 85 shown in FIG. 4 switches the work clutch for turning on and off the transmission to the power take-off shaft 12 between the on and off states by the clutch piston 86.

  The brake hydraulic circuit 60, the steering hydraulic circuit 65, the transmission hydraulic circuit 70, and the work hydraulic circuit 85 are connected to the second hydraulic pump 89 through a regulator valve device 88. The first hydraulic pump 25 and the second hydraulic pump 89 take out the lubricating oil stored in the transmission case 5 as hydraulic oil. Therefore, the mission case 5 becomes a hydraulic oil tank.

  A pair of control valves 38, 38 constituting the actuator driving circuit 30 for the rolling cylinder is configured as an electromagnetic control valve so as to be switched by an electromagnetic operation portion 38e. As shown in FIG. 5, the control device 90 is linked to the electromagnetic operation portion 38 e of the pair of control valves 38, 38, and the tilt sensor 91 is linked to the control device 90.

  The tilt sensor 91 is installed in the mission case 5 so as to detect the left / right tilt angle of the traveling machine body. The inclination sensor 91 outputs the detection result to the control device 90 as an electrical signal.

  The control device 90 is configured using a microcomputer and includes a rolling control means 92. Based on the detection information from the tilt sensor 91 and the tilt angle set by the tilt setting device 93, the rolling control means 92 tilts the horizontal tilt angle of the rotary tiller 7 regardless of the change in the tilt angle detected by the tilt sensor 91. The rolling cylinder 18 is controlled by operating the pair of control valves 38 and 38 so as to be equal to or substantially equal to the set inclination angle by the setting device 93. The inclination setter 93 sets the left / right inclination angle with respect to the horizontal to be maintained by the rotary tiller 7 as the set inclination angle.

  In other words, the rolling control means 92 performs rolling control on the rotary tiller 7 with respect to the traveling machine body by operating the rolling cylinder 18 based on the detection information by the inclination sensor 91 and the setting information by the inclination setting device 93. Regardless of the left / right inclination of the machine body, it is possible to work while keeping the tilling depth on the left / right of the rotary tiller 7 constant or different as set by the inclination setting device 93.

  The ascending control valve 45 and the descending control valve 46 constituting the actuator driving circuit 40 for the lifting cylinder are configured as electromagnetic control valves so as to be switched by the electromagnetic operating portions 45b and 46b. As shown in FIG. 5, the control device 90 is linked to the electromagnetic operating portions 45 b and 46 b of the ascending control valve 45 and the descending control valve 46, and the tilling depth sensor 94 and the angle sensor 95 are linked to the control device 90.

  As shown in FIG. 2, the tilling depth sensor 94 is constituted by a rotating potentiometer in which a sensor body is fixed to a rotary upper cover 96a provided in the rotary tiller 7. The rotating operation shaft of the rotating potentiometer is a rotary upper cover 96a. Is linked to a rotary rear cover 96b pivotally supported around a horizontal axis by a link mechanism 94a.

  That is, the tilling depth sensor 94 detects the tilling depth by the tilling rotor 7a based on the vertical swing angle of the rotary rear cover 96b with respect to the tilling device body, and outputs the detection result to the control device 90 as an electric signal.

  The angle sensor 95 is constituted by a rotation potentiometer in which a rotation operation shaft is linked to a rotation support shaft of the lift arm 15, and detects the rotation angle of the rotation support shaft as a swing angle of the lift arm 15 with respect to the traveling machine body. The detection result is output to the control device 90.

  The control device 90 includes a lift control means 97. The raising / lowering control means 97 controls the raising based on the information detected by the tilling depth sensor 94 and the angle sensor 95 so that the detected tilling depth by the tilling depth sensor 94 is equal to or substantially equal to the set tilling depth by the tilling depth setting device 98. The elevating cylinder 21 is controlled by operating the valve 45 and the lowering control valve 46. The tilling depth setting device 98 sets the tilling depth to be maintained by the rotary tilling device 7 as the set tilling depth.

  That is, the raising / lowering control means 97 raises / lowers the rotary tiller 7 with respect to the traveling machine body by operating the pair of raising / lowering cylinders 21, 21 based on the detection information by the tilling depth sensor 94 and the setting information by the tilling depth setting device 98. Regardless of the forward / backward inclination of the traveling machine body, the rotary tiller 7 can be operated while making the tillage depth the same or substantially the same as the tiller depth by the tiller setting device 98.

  As shown in FIG. 3, the unloading apparatus 100 is configured by including a switching valve 102 connected to the pressure oil supply path 26 via the communication path 101, and an unloading oil path 103 connected to the switching valve 102. When the cylinder 18 and the lifting cylinder 21 are stopped and when the lifting cylinder 21 is lowered, the pressure oil supplied from the first hydraulic pump 25 to the pressure oil supply path 26 is transferred from the pressure oil supply path 26 to the unload oil path 103. The driving load of the first hydraulic pump 25 is reduced by flowing out.

  That is, as shown in FIGS. 3 and 5, the unload device 100 includes a switching valve 102 and an unloading oil passage 103, a drain oil passage 104 connected to the switching valve 102, and the drain oil passage 104. The on-off valve 105 provided, the control valve 107 connected to the operation portion 105 a of the on-off valve 105 via the pilot operation oil passage 106, and the electromagnetic operation portion 107 a of the control valve 107 are linked via the control device 90. An unload control means 108 is provided.

  The communication path 101 communicates the pump port 102P of the switching valve 102 and a portion of the pressure oil supply path 26 that is connected to the input port 33 in the actuator driving circuit 30 for the rolling cylinder.

  The unload oil passage 103 communicates the tank port 102T of the switching valve 102 with the transmission case 5 as a tank. The unload oil passage 103 includes an oil cooler 109 provided between the switching valve 102 and the transmission case 5.

  The switching valve 102 includes a valve chamber 110 in which the pump port 102P and the tank port 102T are open on one end side, a valve body 111 slidably accommodated in the valve chamber 110, and a spring that acts on the back side of the valve body 111. 112 and a back pressure chamber 113 formed of a portion of the valve chamber 110 located behind the valve body 111.

  When the pressure oil acting on the back pressure chamber 113 is discharged to the oil discharge passage 104, the switching valve 102 is the valve head portion of the pressure oil flowing into the valve chamber 110 from the pressure oil supply passage 26 via the communication passage 101. As a result, the valve body 111 is slid against the spring 112, and the valve body head is separated from the valve seat 114 (see FIG. 6) and switched to the open state. When the discharge of the pressure oil from the back pressure chamber 113 is stopped, the switching valve 102 flows into the valve chamber 110 from the pressure oil supply passage 26 via the communication passage 101, and the throttled oil passage provided in the valve body 111. The valve body 111 is slid and operated by the pressure oil and the spring 112 which flows into the back pressure chamber 113 from 115 and acts, and the valve body head is pressed against the valve seat 114 and switched to the closed state.

  When the switching valve 102 is switched to the open state, the pump port 102P and the tank port 102T communicate with each other, and the pressure oil flowing from the pressure oil supply path 26 into the valve chamber 110 via the communication path 101 is unloaded from the tank port 102T. By letting it flow into the load oil passage 103, the pressure oil outflow from the pressure oil supply passage 26 to the unload oil passage 103 is permitted.

  When the switching valve 102 is switched to the closed state, the communication between the pump port 102P and the tank port 102T is cut off, thereby stopping the pressure oil outflow from the pressure oil supply path 26 to the unload oil path 103.

  The on-off valve 105 is opened / closed by the operating portion 105a and the return spring 120, and when it is switched to the open state, the pressure oil acting on the back pressure chamber 113 of the switching valve 102 is discharged by opening the oil drain passage 104. By switching to the passage 104, the switching valve 102 is switched to an open state. The pressure oil discharged from the back pressure chamber 113 to the oil discharge passage 104 flows into the unload oil passage 103 and returns to the mission case 5 as a tank.

  When the on-off valve 105 is switched to the closed state, the switch valve 102 is closed by closing the drain oil passage 104 and stopping the discharge of the pressure oil from the back pressure chamber 113 of the switch valve 102 to the drain oil passage 104. Switch to the state.

  When the control valve 107 is switched between the unload position [on] and the unload release position [off] by the electromagnetic operation unit 107a and the return spring 130, and is switched to the unload position [on], the actuator is driven. The pilot oil pressure supplied from the pilot oil passage 38b of the circuit 30 to the pilot oil passage 131 is supplied to the pilot operation oil passage 106 and supplied to the operation portion 105a of the on-off valve 105, and the on-off valve 105 is switched to the open state by the pilot oil pressure. Manipulate.

  When the control valve 107 is switched to the unload release position [off], the control valve 107 discharges the pilot hydraulic pressure from the operation portion 105a of the on-off valve 105 via the pilot operation oil passage 106, and closes the on-off valve 105. Switch operation. The pilot hydraulic pressure discharged from the operating portion 105a of the on-off valve 105 to the pilot operating oil passage 106 flows from the drain oil passage 132 into the unload oil passage 103 and returns to the mission case 5 as a tank.

  The unload control means 108 opens and closes the control valve 107 when the actuator drive circuit 30 is operated to drive the rolling cylinder 18 or when the actuator drive circuit 40 is operated to drive the elevating cylinder 21 upward. The valve 105 is switched to the closed state, and the actuator drive circuit 30 and the actuator drive circuit 40 are operated to stop the rolling cylinder 18 and the lift cylinder 21 or the actuator drive circuit 30 is operated to stop the rolling cylinder 18. When the actuator driving circuit 40 is operated to operate the elevating cylinder 21 downward, the control valve 107, the actuator driving circuit 30, and the actuator are controlled so that the control valve 107 switches the on-off valve 105 to the open state. Drive times It is made to coordinate the and 40.

  That is, the unload control means 108 outputs the actuator drive operation signal by the rolling control means 92 and switches one of the pair of control valves 38, 38 to the drive position, or the lift control means 97 raises the actuator. When a drive operation signal is output and the lift control valve 45 is switched to the drive position, information indicating that the rolling control means 92 or the lift control means 97 has output an actuator drive or actuator lift drive operation signal is input. Based on the input, an unload release operation signal is output as an electric signal to the electromagnetic operation unit 107a of the control valve 107, and the control valve 107 is switched to the unload release position [off].

  In the unload control means 108, the rolling control means 92 outputs an actuator stop operation signal to switch the pair of control valves 38, 38 to the neutral position, and the lift control means 97 outputs an actuator stop operation signal. The raising control valve 45 and the lowering control valve 46 are switched to the stop position, or the rolling control means 92 outputs an actuator stop operation signal to switch the pair of control valves 38, 38 to the neutral position. When the elevation control means 97 outputs an operation signal for the actuator lowering operation to switch the ascent control valve 45 to the stop position and to switch the lowering control valve 46 to the lowering operation position, the actuator drive circuit 30 and the actuator drive circuit 40 are operated. Outputs operation signals for actuator stop and actuator lowering operations Enter the information that was to operate switches the control valve 107 is output to the electromagnetic operation section 107a of the control valve 107 an operation signal unloaded electric signal based on the input to the unload position [on].

  Therefore, when the operation valve 32 for the rolling cylinder 18 is switched to the actuator drive position, or the lift operation valve 42 for the lift cylinder 21 is switched to the actuator drive position, the unload device 100 is By switching the control valve 107 to the unload release position [off] by linking the control valve 107 by the unload control means 108 with the actuator drive circuit 30 and the actuator drive circuit 40, the on-off valve 105 is piloted by the control valve 107. The operation is switched to the closed state by discharging the hydraulic pressure, and the discharge of the pressure oil from the back pressure chamber 113 is stopped by the on-off valve 105, so that the switching valve 102 is switched to the closed state, and the pressure oil supply path 26 to the unload oil path Stop the pressure oil outflow to 103, the first hydraulic pump The pressure oil supplied from 5 to the pressure oil supply passage 26 is supplied to the rolling cylinder 18 and the elevating cylinder 21 so that the rolling cylinder 18 can be driven to the extending and shortening side, and the elevating cylinder 21 is moved upward (extended side). To be able to drive.

  In the unloading apparatus 100, the operation valve 32 for the rolling cylinder 18 is switched to the neutral position, the ascending operation valve 42 for the elevating cylinder 21 is switched to the refueling stop position, and the descending operation valve 43 is switched to the lock position. The operation valve 32 for the rolling cylinder 18 is switched to the neutral position, the ascending operation valve 42 for the elevating cylinder 21 is in the oil supply stop position, and the descending operation valve 43 is in the oil discharge position. When the switching operation is performed, the control valve 107 is switched to the unloading position [on] by linking the control valve 107 with the actuator driving circuit 30 and the actuator driving circuit 40 by the unload control means 108, thereby opening the on-off valve 105. Switching to the open state by supplying pilot hydraulic pressure from the control valve 107 The switching valve 102 is switched to the open state by allowing the pressure oil to be discharged from the back pressure chamber 113 by the on-off valve 105, so that the pressure oil flows from the pressure oil supply path 26 to the unload oil path 103. The pressure oil supplied to the pressure oil supply path 26 from the first hydraulic pump 25 is allowed to flow out from the switching valve 102 to the unload oil path 103 to reduce the driving load of the first hydraulic pump 25.

  FIG. 6 is a plan view showing a valve device including the switching valve 102, the on-off valve 105, and the control valve 107. FIG. 7 is a side view showing a valve device including the switching valve 102, the on-off valve 105, and the control valve 107. 8 is a cross-sectional view taken along line VIII-VIII in FIG. As shown in these drawings, the valve device including the switching valve 102, the on-off valve 105, and the control valve 107 includes a valve case 140 formed so that the shape in plan view is rectangular. The valve case 140 includes a valve case portion 116 of the switching valve 102 located on one end side in the long side direction of the valve case 140 and a valve case of the on-off valve 105 located on the other end side in the long side direction of the valve case 140. And a valve case portion 134 of the control valve 107 located on the other end side in the long side direction of the valve case 140. The valve case portion 116 of the switching valve 102, the valve case portion 122 of the on-off valve 105, and the valve case portion 134 of the control valve 107 are integrally formed.

  The valve body 111 of the switching valve 102 and the spool 133 of the control valve 107 are incorporated in the valve case 140 so as to be aligned in the sliding direction of the valve body 111 of the switching valve 102. The valve body 111 of the switching valve 102 and the spool 133 of the control valve 107 are arranged at the center of the valve case 140 in the short side direction. The valve element 111 of the switching valve 102 and the spool 133 of the control valve 107 are arranged in a state in which their axial centers are positioned on a straight line. The spool 121 of the on-off valve 105 is incorporated in the valve case 140 so as to be aligned with the spool 133 of the control valve 107 in a direction perpendicular to the sliding direction of the valve body 111 of the switching valve 102. The sliding direction of the valve body 111 of the switching valve 102, the spool 133 of the control valve 107 and the spool 121 of the on-off valve 105 is the long side direction of the valve case 140.

  On the surface side of the valve case 140, a pump port 102 </ b> P of the switching valve 102 is provided between the control valve 107 and the valve chamber 110 of the switching valve 102. A pilot pressure inlet 141 for supplying pilot hydraulic pressure to the control valve 107 and a tank port of the switching valve 102 at the end of the valve case 140 opposite to the side where the on-off valve 105 is located with respect to the switching valve 102 and the control valve 107. 102T are arranged side by side in the long side direction of the valve case 140. A pilot operating oil passage 106 that connects the operating portion 105 a of the on-off valve 105 and the output port of the control valve 107 is formed inside the valve case 140. An upstream portion 104 a located on the upstream side of the on-off valve 105 and a downstream portion 104 b located on the downstream side of the on-off valve 105 in the oil discharge passage 104 are provided inside the valve case 140. The downstream portion 104b of the drain oil passage 104 and the drain oil passage 132 are provided in the valve case 140 so as to communicate with the tank port 102T of the switching valve 102.

[Another embodiment]
FIG. 9 is a cross-sectional view showing a valve device including another embodiment. As shown in this figure, the valve device including another embodiment is configured to include a single valve case 150, and the valve case 150 includes a pair of control valves 38, 38 included in the actuator drive circuit 30 for the rolling cylinder. The connector 151 connected by the lead wire 151a is incorporated in the control valve 107 provided in the unloading device 100 and the electromagnetic operating portions 38e and 107a of the control valves 38 and 107.

  The valve case 150 includes a plurality of mounting holes 152 provided on the outer peripheral side of the valve case 150 so as to be distributed in the circumferential direction of the valve case 150, and the transmission case 5 or other transmission holes are connected to the mounting holes 52 by connecting bolts. It is comprised so that it may mount | wear with the support member which consists of a valve apparatus. The pair of control valves 38 and 38 and one control valve 107 are incorporated in an arrangement in which the sliding direction of the spool is parallel or substantially parallel. Since the control valve 38 and the control valve 107 are valves of the same form (type), they can be arranged compactly and efficiently in one valve case 150.

[Another Example]
(1) In the above-described embodiment, an example is shown in which the control valve 107 is configured to be linked to the actuator drive circuits 30 and 40 that are automatically controlled. The actuator driving circuit may be configured by including an operation valve that can be operated, and the actuator driving circuit that is manually operated and the control valve 107 may be linked to each other.

(2) In the above-described embodiment, an example in which the elevating cylinder 21 and the rolling cylinder 18 are provided as hydraulic actuators has been described. However, an operation in which a hydraulic motor that drives various hydraulic cylinders and working devices with different operation targets is provided as the hydraulic actuator. It can also be applied to machines.

(3) Although the example provided with the rotary plowing device 7 has been described in the above-described embodiment, various working devices such as a mowing device, a spraying device for drugs, fertilizers, and the like may be provided.

  INDUSTRIAL APPLICABILITY The present invention is applicable to various working machines such as combine machines, backhoes and other construction machines in addition to tractors.

7 Working device 18, 21 Hydraulic actuator 25 Hydraulic pump 26 Pressure oil supply path 30, 40 Actuator drive circuit 102 Switching valve 103 Unload oil path 104 Oil drain path 105 Open / close valve 107 Control valve 111 Valve element 113 Back pressure chamber 116 Switching valve Valve case part 121 spool of on-off valve 122 valve case part of on-off valve 133 spool of control valve 134 valve case part of control valve 140 valve case

Claims (5)

Switchable between an open state allowing pressure oil flow from the pressure oil supply path for supplying pressure oil from the hydraulic pump to the actuator drive circuit to the unload oil path and a closed state stopping the pressure oil flow; and A switching valve operated to the closed state by pressure oil from the pressure oil supply passage acting on a back pressure chamber;
An open / close valve that is switchable between an open state for discharging pressure oil from the back pressure chamber to the oil discharge passage and a closed state for stopping discharge of the pressure oil;
A control valve for switching the on-off valve by pilot hydraulic pressure,
When the actuator drive circuit is operated to drive a hydraulic actuator, the control valve switches the on-off valve to the closed state, and when the actuator drive circuit is operated to stop the hydraulic actuator, the control An unloading device for a working machine, wherein the actuator drive circuit and the control valve are linked so that the valve switches the open / close valve to the open state.   The valve body of the switching valve and the spool of the control valve are aligned in the sliding direction of the valve body, and the spool of the control valve and the spool of the on-off valve are orthogonal to the sliding direction of the valve body. The unloading device for a working machine according to claim 1, wherein the valve body, the spool of the control valve, and the spool of the on-off valve are incorporated in a valve case in an array.   The unloading of a working machine according to claim 2, wherein the valve case is configured by integrally forming a valve case part of the switching valve, a valve case part of the on-off valve, and a valve case part of the control valve. apparatus.   The unloading device for a working machine according to any one of claims 1 to 3, further comprising a lifting cylinder that lifts and lowers the working device with respect to the traveling machine body as the hydraulic actuator.   The unloading device for a working machine according to any one of claims 1 to 4, further comprising a rolling cylinder that performs a rolling operation of the working machine with respect to the traveling machine body as the hydraulic actuator.

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